Up to the present, there have been developed a large number of psychotropic agents for the therapy of anxiety neurosis, schizophrenia, depression, etc. Yet, most of these drugs accompany various side-effects upon continuous administration, or the like, such as excessive sedation, addiction, dyskinesia and Parkinson disease, and they are not entirely satisfactory.
Meanwhile, Tetrahedron 44(18), 5921-5928 (1988) teaches methods for synthesizing 5-acetyl-3-cyano-2-(2-diethylaminoethyl)thio-4-phenylthiophene and 5-benzoyl-4-chloro-3-cyano-2((2-dimethylaminoethyl)thio)thiophene. Eur. J. Med. Chem. Chim. Ther. 12(6), 557-563 (1977)teaches 2-((2-piperidinoethyl)thio)thiophene, 2-((2-morpholinoethyl)thio)thiophene, and others having an antiviral activity. Japanese Patent Unexamined Publication No. 133989/1977 discloses compounds such as 1-[2-(2thienylthio)ethyl]-4-(N-phenyl-N-propionylamino)piperidine having a hypotensive action. Japanese Patent Unexamined Publication No. 81582/1981 discloses N-[3-[[5-(dimethylamino)- methyl-4-methyl-2-thienyl]thio]propyl]-isoindole-l,3(2H)-dione as a synthetic intermediate of a compound having a histamine H.sub.2 antagonistic action. Also, Chemical Abstracts 112(9): 77137p shows N-[2-(2-thienylthio)ethyl]-2-oxo-5-hydroxypyrrolidine. However, there have not been reported action of these compounds on the central nervous system.
Japanese Patent Unexamined Publication No. 115568/1985 discloses methyl (2RS, 5R)-3-[2-(5-carbamoyl-2-thienyl)ethyl]-5-phenyl-2 oxazolidinecarboxylate having an antidiabetic effect. Japanese Patent Unexamined Publication No. 213278/1989 discloses 1-[2-(2-thienyl)ethyl]-4-(2-ethyl-1,3,4-oxadiazol-5-yl)-4-(N-phenylpropion amido)piperidine having an analgesic action. Yakugaku Zasshi 104(6), 680-690 (1984) reports 3-[2-(5-acetyl-2-thienyl)ethyl]-2,4-oxazolidincdione, etc. having an antiulcer action. Furthermore, Japanese Patent Unexamined Publication Nos. 185777/1985 and 45381/1989, US Patent No. 4032531, Japanese Patent Unexamined Publication Nos. 151183/1977, 93334/1974 and 40582/1975, US Patent No. 3919243, Japanese Patent Examined Publication No. 14557/1967, U.S. Pat. No. 3171838, UK Patent No. 1294720, and Japanese Patent Unexamined Publication Nos. 85576/1973, 85578/1973 and 206558/1983 disclose thiophene compounds. However, these compounds have not been reported as having an action on central nervous system.
As a compound having a psychotropic action, Japanese Patent Unexamined Publication No. 156879/1977 reports 4-2-(4- acetylaminomethylphenyl)ethyl-1-phenylpiperazine.